Associate disabled test cases with existing open issues, update
comments to be consistent, disable a few additional test cases.
The goal is for all enabled test to pass 100% reliably.
The following test cases have been disabled due to infrequent
failures during automated testing. Several of these test cases
were previous disabled only for the kmemleak builder but have
subsequently been observed on other automated builders.
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov> Reviewed-by: George Melikov <mail@gmelikov.ru> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #5649